Solved: Cold As Ice

[pnegyesi]

An accident helped. No15 is Otto Mathe's Lieferfahrrad (Transportation Bicycle) from 1940
And on No25 his self-made racecar is visible at the start of the ski-joring race in 1955

[pnegyesi]

Which leaves No8 and No19 as the last pair. (I was wrong after all )
If No19 shows the Ice Hall in Kassel, then we have a connection Am I right?

[Wendax]

An accident helped. No15 is Otto Mathe's Lieferfahrrad (Transportation Bicycle) from 1940
And on No25 his self-made racecar is visible at the start of the ski-joring race in 1955

Yes, during WW2 Otto Mathé developed his fuel additive "Mathé Universal" which he delivered by bike in the beginning. His race car, the Fetzenflieger, appeared at AutoPuzzles before: http://www.autopuzzles.com/forum/index.php?topic=10239.0

[Wendax]

Which leaves No8 and No19 as the last pair. (I was wrong after all )
If No19 shows the Ice Hall in Kassel, then we have a connection Am I right?

No points for finding the last pair. 
I don't know where picture #19 was taken, so you have to look for another connection.

[Tom_I]

#8, the Henschel steam truck, used mechanical features designed by the American company Doble, and my guess is that the skaters in #19 are performing a Paso Doble (for which there is a set sequence of steps and moves), which is often included in ice dancing competitions.

[Wendax]

#8, the Henschel steam truck, used mechanical features designed by the American company Doble, and my guess is that the skaters in #19 are performing a Paso Doble (for which there is a set sequence of steps and moves), which is often included in ice dancing competitions.

Hooray, you put this frosty madness to an end. That was the last missing connection. Congratulation!  

[Wendax]

Dear participants, I'm proud to have added "looking for ice cream vans" to your favorite pastimes. I hope you had as much fun puzzling as I had conceiving this puzzle and watching you solve it. It's about time to think about a new group puzzle, maybe garbage trucks? 

The final score:

woodinsight: 5 points
Tom_I: 5 points
pnegyesi: 4 points
Julien1A: 1 point

Well done, gentlemen.

[Tom_I]

An excellent puzzle - thank you!

[woodinsight]

Thank you - it's the first time I tried a puzzle like this and I enjoyed it very much.
- not sure about Garbage Trucks though

[Allemano]

Though I didn't score anything here I enjoyed reading the replies of this quirky and well arranged puzzle!

[pnegyesi]

Thanks, this was fun. Onwards and upwards